Board-to-board connector

Abstract

To provide a technique capable of crossing a position of a contact point when removing a weight to a contact to an initial position.SOLUTION: A spring piece 12 of each contact 5 contains: a first spring part 15 that is extended between a contact point 13 and a fixing part 10; and a second spring part 16 that is extended to a lower direction from the contact point 13. In the plurality of contacts 5, when a board to board connector 4 is mounted onto a main substrate 2, the second spring part 16 is separated from the main substrate 2, In the plurality of contacts 5, when the contact point 13 is deviated to a lower side after the spring piece 12 receives the weight from a following substrate 3, the first spring part 15 is deformed, and the second spring part 16 is deformed in accordance with a contact with the main substrate 2. In at least any one of the plurality of contacts 5, the second spring part 16 is continuously contacted to the main substrate 2 after the contact point 13 is deviated to an upper direction by removing the weight.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a board-to-board connector.

Background Art

[0002] Patent Document 1 discloses a contact 100 for a board-to-board connector as shown in FIG. 9 of the present application. The contact 100 has, in this order of description, a soldering portion 101 soldered to a circuit board, an elastic piece 104 having a connecting portion 102 and a contact portion 103 held by a housing.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the contact 100 of Patent Document 1 above, in order to improve transmission characteristics, the transmission path length from the contact portion 103 to the soldering portion 101 is designed to be short. That is, the length of the elastic piece 104 is not sufficiently ensured. Therefore, when the contact portion 103 is lowered by a predetermined stroke while the elastic piece 104 is deformed, the elastic piece 104 may be plastically deformed. When the elastic piece 104 is plastically deformed, even if the load on the elastic piece 104 is removed, plastic strain remains in the elastic piece 104, and the contact portion 103 cannot be returned to the initial position.

[0005] An object of the present disclosure is to provide a technique for bringing the position of the contact portion when the load on the contact is removed closer to the initial position.

Means for Solving the Problems

[0006] From the perspective of this disclosure, a board-to-board connector is mounted on a first substrate and sandwiched between the first substrate and a second substrate to electrically connect a plurality of first electrode pads of the first substrate and a plurality of second electrode pads of the second substrate, comprising a plurality of contacts and a housing that holds the plurality of contacts, wherein the housing has a housing lower surface that can face the first substrate and a housing upper surface that can face the second substrate, and each contact comprises a fixing portion fixed to the housing, a mounting portion protruding from the fixing portion and solderable to a corresponding first electrode pad, and a spring piece extending from the fixing portion and having a contact portion that can contact a corresponding second electrode pad, wherein the spring piece of each contact has a first spring piece extending between the contact portion and the fixing portion A board-to-board connector is provided, comprising a spring portion and a second spring portion extending from the contact portion in a direction viewed from the upper surface of the housing to the lower surface of the housing, wherein in the plurality of contacts, when the board-to-board connector is mounted on the first board, the second spring portion is separated from the first board, and when the contact portion is displaced in a direction viewed from the upper surface of the housing to the lower surface of the housing due to the spring piece receiving a load from the second board, the first spring portion deforms and the second spring portion deforms in contact with the first board, and in at least one of the plurality of contacts, after the load is removed and the contact portion is displaced in a direction viewed from the lower surface of the housing to the upper surface of the housing, the second spring portion continues to be in contact with the first board. The second spring portion may have at least one bent portion. The second spring portion may have a curved portion that is capable of contacting the first substrate and is convex in the direction viewed from the upper surface of the housing to the lower surface of the housing. The fixing portion may be fixed to the housing by press-fitting. The fixing portion may be fixed to the housing by insert molding. [Effects of the Invention]

[0007] According to this disclosure, the position of the contact portion when the load on the contact is removed can be brought closer to the initial position. [Brief explanation of the drawing]

[0008] [Figure 1] This is a perspective view of electronic equipment. [Figure 2] This is a cross-sectional perspective view of a board-to-board connector. [Figure 3] This is a perspective view of contacts. [Figure 4] This diagram shows how to use a board-to-board connector. [Figure 5] This diagram shows how to use a board-to-board connector. [Figure 6] This diagram shows how to use a board-to-board connector. [Figure 7] This graph shows the change in the height position of the contact point. [Figure 8] This diagram shows how to use a board-to-board connector. (Comparative example) [Figure 9] This is a simplified diagram of Figure 1 in Patent Document 1. [Modes for carrying out the invention]

[0009] (Embodiment) The embodiments of this disclosure will be described below with reference to Figures 1 to 7.

[0010] Figure 1 shows electronic device 1. As shown in Figure 1, electronic device 1 includes a main board 2 (first board), a secondary board 3 (second board), and a board-to-board connector 4.

[0011] The main substrate 2 includes a substrate body 2A and a plurality of pairs of main electrode pads 2C (first electrode pads) provided on the connector mounting surface 2B of the substrate body 2A. Each pair of main electrode pads 2C includes a constant connection pad 2D and a temporary connection pad 2E. The constant connection pad 2D and the temporary connection pad 2E are electrically connected to each other. However, the constant connection pad 2D and the temporary connection pad 2E may be electrically insulated from each other. The temporary connection pad 2E can be omitted.

[0012] The sub-substrate 3 includes a substrate body 3A and a plurality of sub-electrode pads 3C (second electrode pads) provided on the connector facing surface 3B of the substrate body 3A.

[0013] The substrate body 2A of the main substrate 2 and the substrate body 3A of the sub-substrate 3 are, for example, rigid substrates such as paper phenolic substrates or glass epoxy substrates, or flexible substrates.

[0014] The board-to-board connector 4 is mounted on the connector mounting surface 2B of the substrate body 2A of the main substrate 2. The board-to-board connector 4 is sandwiched between the main substrate 2 and the sub-substrate 3 that are parallel to each other, thereby electrically connecting the plurality of pairs of main electrode pads 2C of the main substrate 2 and the plurality of sub-electrode pads 3C of the sub-substrate 3 to each other. The direction in which the main substrate 2, the board-to-board connector 4, and the sub-substrate 3 overlap is hereinafter referred to as the vertical direction. The direction of viewing the main substrate 2 from the board-to-board connector 4 is defined as downward, and the direction of viewing the sub-substrate 3 from the board-to-board connector 4 is defined as upward. However, the upward, downward, and vertical directions do not limit the posture of the board-to-board connector 4 during use.

[0015] The board-to-board connector 4 includes a plurality of metal contacts 5 and a housing 6 made of insulating resin that houses the plurality of contacts 5.

[0016] The housing 6 is formed in a rectangular flat plate shape in plan view. The housing 6 has a housing lower surface 6A facing downward and a housing upper surface 6B facing upward.

[0017] The plurality of contacts 5 are all housed in the housing 6 in the same orientation with respect to each other. Hereinafter, the longitudinal direction and the lateral direction in the plan view of each contact 5 will be simply referred to as the longitudinal direction and the lateral direction, respectively.

[0018] As shown in FIG. 2, a plurality of cavities 7 are formed in the housing 6. Each cavity 7 is formed so as to penetrate the housing 6 in the vertical direction. That is, each cavity 7 is formed so as to open to the housing lower surface 6A and the housing upper surface 6B of the housing 6. A plurality of contacts 5 are respectively housed in the plurality of cavities 7.

[0019] FIG. 3 shows a perspective view of each contact 5. Since the plurality of contacts 5 have the same shape, hereinafter, one representative contact 5 will be described.

[0020] As shown in FIG. 3, the contact 5 is formed to be line symmetric when viewed from the longitudinal direction. The contact 5 includes a fixing portion 10, a mounting portion 11, and a spring piece 12.

[0021] The fixing portion 10 is a portion fixed to the housing 6 by press fitting. The thickness direction of the fixing portion 10 is equal to the longitudinal direction.

[0022] The mounting portion 11 is a portion where soldering can be performed to the corresponding always-connected pad 2D. The mounting portion 11 protrudes from the lower end 10A of the fixing portion 10. The thickness direction of the mounting portion 11 is equal to the vertical direction. Hereinafter, for convenience of explanation, the direction in which the mounting portion 11 protrudes from the fixing portion 10 will be referred to as the front, and the opposite direction will be referred to as the rear.

[0023] The spring piece 12 has a contact portion 13 that can contact the corresponding slave electrode pad 3C. The spring piece 12 extends from the upper end 10B of the fixing portion 10.

[0024] The spring piece 12 includes a first spring portion 15 and a second spring portion 16. The fixing portion 1�, the first spring portion 15, the contact portion 13, and the second spring portion 16 are connected in this order of description in the developed view of the contact 5.

[0025] The first spring portion 15 extends between the fixed portion 10 and the contact portion 13. The first spring portion 15 is inclined to be an upward slope towards the front.

[0026] The contact portion 13 is provided at the tip of the first spring portion 15. The contact portion 13 is curved so as to be convex upwards.

[0027] The second spring portion 16 extends downward from the contact portion 13. The second spring portion 16 includes an upper inclined portion 16A that slopes downward toward the rear and a lower inclined portion 16B that slopes downward toward the front. The upper inclined portion 16A and the lower inclined portion 16B are connected downward from the contact portion 13 in this order. A bent portion 16C is formed between the upper inclined portion 16A and the lower inclined portion 16B, which bends so as to be convex toward the rear. That is, the upper inclined portion 16A and the lower inclined portion 16B are connected to each other via the bent portion 16C. A curved portion 16D that is convex toward the downward is formed at the lower end of the second spring portion 16. The lower end of the second spring portion 16 corresponds to the free end of the spring piece 12.

[0028] As shown in Figure 4, in the unloaded state of the spring piece 12, the contact portion 13 protrudes above the upper surface 6B of the housing. Also, in this state, the mounting portion 11 protrudes below the lower surface 6A of the housing. Similarly, the curved portion 16D of the second spring portion 16 of the spring piece 12 protrudes below the lower surface 6A of the housing.

[0029] The contact 5 is typically manufactured by punching and bending a single sheet of metal. The housing 6 is typically formed by injection molding.

[0030] Next, the method of using the board-to-board connector 4 will be explained with reference to Figures 4 to 6.

[0031] First, the board-to-board connector 4 is mounted on the connector mounting surface 2B of the main board 2. Specifically, the mounting portion 11 of each contact 5 is soldered to the corresponding permanent connection pad 2D of the main board 2. Figure 4 shows the state after each contact 5 has been soldered to the corresponding permanent connection pad 2D, but the spring piece 12 of each contact 5 has not yet made contact with the secondary board 3. In this state, the curved portion 16D of the second spring portion 16 of the spring piece 12 is slightly above the corresponding temporary connection pad 2E of the main board 2. In short, when the board-to-board connector 4 is mounted on the main board 2, the second spring portion 16 is above the main board 2. This ensures that the mounting portion 11 of each contact 5 is closer to the main board 2 than the second spring portion 16, so that the mounting portion 11 of each contact 5 can be easily soldered to the corresponding permanent connection pad 2D of the main board 2.

[0032] In this state, to electrically connect the main board 2 and the secondary board 3, the secondary electrode pad 3C of the secondary board 3 is positioned vertically opposite the contact portion 13, and the secondary board 3 is pressed toward the board-to-board connector 4. As shown in Figure 5, the secondary electrode pad 3C comes into contact with the contact portion 13, and the spring piece 12 receives a downward load from the secondary board 3, causing the contact portion 13 to displace downward by a predetermined stroke. This stroke can typically be easily controlled by interposing a spacer of a predetermined thickness between the housing 6 of the board-to-board connector 4 and the secondary board 3. When the contact portion 13 displaces downward by a predetermined stroke, the first spring portion 15 deforms, and the second spring portion 16 deforms in contact with the main board 2.

[0033] Specifically, the first spring portion 15 deforms so as to bend downward. When the contact portion 13 is displaced downward by a predetermined stroke amount as described above, the deformation of the first spring portion 15 may exceed the elastic range and become plastic deformation.

[0034] Furthermore, the second spring portion 16 deforms so as to be compressed vertically as the contact portion 13 is displaced downward and the second spring portion 16 comes into contact with the temporary connection pad 2E of the main substrate 2. Specifically, the second spring portion 16 deforms so as to reduce the angle θ formed by the upper inclined portion 16A and the lower inclined portion 16B. At this time, the deformation of the second spring portion 16 is typically elastic because the spring length of the second spring portion 16 is sufficiently ensured.

[0035] Next, to release the electrical connection between the main board 2 and the secondary board 3, first, the secondary board 3 is moved upward, thereby moving it away from the board-to-board connector 4. As a result, the load that the spring piece 12 was receiving from the secondary board 3 is removed, and the contact portion 13 is displaced upward as shown in Figure 6. At this time, the spring piece 12 remains in continuous contact with the main board 2. Specifically, the second spring portion 16 remains in continuous contact with the corresponding temporary connection pad 2E of the main board 2. The fact that the second spring portion 16 remains in continuous contact with the main board 2 even after the load that the spring piece 12 was receiving from the secondary board 3 is removed means that the elastic restoring force of the second spring portion 16 is acting upward on the contact portion 13. Therefore, compared to the case where the spring piece 12 has only the first spring portion 15 and not the second spring portion 16, the position of the contact portion 13 can be brought closer to the initial position of the contact portion 13 shown in Figure 4. For the sake of explanation, we will define the height position Z of the contact portion 13 below. That is, as shown in Figure 6, the height position Z of the contact portion 13 is defined as the vertical distance from the lower surface 6A of the housing 6 to the top of the contact portion 13. Below, we will focus on this height position Z and explain in detail the technical significance of the elastic restoring force of the second spring portion 16.

[0036] Figure 7 shows a graph illustrating the change in the height position Z of the contact portion 13. In the graph of Figure 7, the horizontal axis represents time, and the vertical axis represents the height position Z of the contact portion 13. The solid line A in the graph of Figure 7 corresponds to this embodiment. At time t0, the board-to-board connector 4 is mounted on the main board 2. Hereinafter, the height position Z at time t0 will be referred to as the initial position Z0. Next, from time t1 to time t2, the secondary board 3 is pressed towards the board-to-board connector 4 to electrically connect the main board 2 and the secondary board 3. Hereinafter, the height position Z at time t2 will be defined as the connection position Z1. Next, from time t3 to time t4, the secondary board 3 is moved upward away from the board-to-board connector 4 to release the electrical connection between the main board 2 and the secondary board 3. Hereinafter, the height position Z at time t4 will be defined as the restored position ZA. Subsequently, inter-board connection is performed from time t5 to time t6, inter-board connection is released from time t7 to time t8, and inter-board connection is performed from time t9 to time t10. From time t4 onward, when inter-board connection is performed, the height position Z is the connection position Z1, and when inter-board connection is released, the height position Z is the restored position ZA. In this way, the height position Z of the contact portion 13 oscillates back and forth between the connection position Z1 and the restored position ZA.

[0037] Here, if the first spring portion 15 undergoes plastic deformation when the auxiliary board 3 is pressed toward the board-to-board connector 4 between time t1 and time t2 to electrically connect the main board 2 and the auxiliary board 3, then residual strain will remain in the first spring portion 15 when the electrical connection between the main board 2 and the auxiliary board 3 is released between time t3 and time t4. In short, the first spring portion 15 cannot return to its original shape. As a result, the restored position ZA is lower than the initial position Z0.

[0038] The thick line B in the graph of Figure 7 corresponds to the comparative example of this disclosure. In this comparative example, the spring piece 12 has only the first spring portion 15 and no second spring portion 16. In this comparative example, when the electrical connection between the main board 2 and the auxiliary board 3 is released by moving the auxiliary board 3 upward from the board-to-board connector 4 between time t3 and time t4, the height position Z after release is lower than the restored position ZA. For the sake of explanation, in this comparative example, the height position Z in the state of board-to-board connection release will be defined as the restored position ZB.

[0039] The reason why the restored position ZA is closer to the initial position Z0 than the restored position ZB is as follows. In this embodiment, as described above, the second spring portion 16 continues to be in contact with the main substrate 2 even after the load that the spring piece 12 was receiving from the dependent substrate 3 has been removed. This means that the elastic restoring force of the second spring portion 16 is acting upward on the contact portion 13. Therefore, in this embodiment, the height position Z of the contact portion 13 can be brought closer to the initial position Z0 compared to the comparative example. In the substrate-to-substrate connection release state shown in Figure 6, the elastic restoring force of the first spring portion 15 acts downward on the contact portion 13, and the elastic restoring force of the second spring portion 16 acts upward, and the elastic restoring forces of the first spring portion 15 and the elastic restoring force of the second spring portion 16 are balanced in the vertical direction. If, hypothetically, the second spring portion 16 could be cut off in the state where the connection between the substrates is disconnected as shown in Figure 6, the first spring portion 15 would lose the elastic restoring force it received from the second spring portion 16, and would descend due to the elastic restoring force of the first spring portion 15. As a result, the height position Z of the contact portion 13 would change to the restored position ZB shown in Figure 7.

[0040] The embodiments described above have the following features.

[0041] As shown in Figures 1 to 6, the board-to-board connector 4 is mounted on the main board 2 (first board) and sandwiched between the main board 2 and the secondary board 3 (second board), thereby electrically connecting the multiple pairs of main electrode pads 2C (first electrode pads) on the main board 2 and the multiple secondary electrode pads 3C (second electrode pads) on the secondary board 3. The board-to-board connector 4 includes a plurality of contacts 5 and a housing 6 that holds the plurality of contacts 5. The housing 6 has a lower housing surface 6A that can face the main board 2 and an upper housing surface 6B that can face the auxiliary board 3. Each contact 5 includes a fixing portion 10 fixed to the housing 6, a mounting portion 11 protruding from the fixing portion 10 and capable of being soldered to the corresponding main electrode pad pair 2C, and a spring piece 12 extending from the fixing portion 10 and having a contact portion 13 capable of contacting the corresponding secondary electrode pad 3C. Each spring piece 12 of the contact 5 includes a first spring portion 15 extending between the contact portion 13 and the fixed portion 10, and a second spring portion 16 extending downward from the contact portion 13. When the board-to-board connector 4 is mounted on the main board 2 with multiple contacts 5, the second spring portion 16 is separated from the main board 2. In multiple contacts 5, when the contact portion 13 is displaced downward due to the spring piece 12 receiving a load from the secondary substrate 3, the first spring portion 15 deforms and the second spring portion 16 deforms in contact with the main substrate 2. In at least one of the multiple contacts 5, as shown in Figure 6, after the contact portion 13 is displaced upward due to the removal of the load, the second spring portion 16 continues to contact the main substrate 2. With the above configuration, the height position Z of the contact portion 13 when the load on the contact 5 is removed can be brought closer to the initial position Z0.

[0042] In the above embodiment, it was assumed that in at least one of the multiple contacts 5, after the contact portion 13 is displaced upward due to the removal of the load, the second spring portion 16 continues to contact the main substrate 2. However, instead, as shown in Figure 6, in all of the multiple contacts 5, after the contact portion 13 is displaced upward due to the removal of the load, the second spring portion 16 may continue to contact the main substrate 2.

[0043] The above technical effect, which allows the height position Z of the contact portion 13 when the load on the contact 5 is removed to be brought closer to the initial position Z0, will improve the coplanarity of the contact portions 13 of the multiple contacts 5 in the state shown in Figure 6. Furthermore, the above technical effect will also contribute to improving the wiping action.

[0044] Furthermore, as shown in Figure 4, the second spring portion 16 has a bent portion 16C. With the above configuration, the spring length of the second spring portion 16 can be effectively secured. In this embodiment, the second spring portion 16 has one bent portion 16C, but instead, the second spring portion 16 may have multiple bent portions 16C.

[0045] Furthermore, as shown in Figure 4, the second spring portion 16 has a curved portion 16D that is convex downward and can contact the main substrate 2. With this configuration, when the second spring portion 16 contacts the main substrate 2, the second spring portion 16 slides in the longitudinal direction, thereby achieving smooth elastic deformation of the second spring portion 16.

[0046] Furthermore, as shown in Figure 4, the fixing part 10 is fixed to the housing 6 by press-fitting. However, instead, the fixing part 10 may be fixed to the housing 6 by insert molding.

[0047] (modified version) The above embodiment can be modified as follows, for example.

[0048] That is, as shown in Figure 4, in the above embodiment, the second spring portion 16 has a bent portion 16C that bends to become convex to the rear. However, instead, as shown in Figure 8, the second spring portion 16 may have a bent portion 16E that bends to become convex to the front. With the above configuration as well, the spring length of the second spring portion 16 can be effectively secured. [Explanation of Symbols]

[0049] 1 Electronic equipment 2 Main board 2A Main board 2B connector mounting side 2C Main Electrode Pad Pair 2D Always-On Pad 2E Temporary Connection Pad 3 Sub-substrate 3A Main board 3B connector opposing side 3C Sub-electrode Pad 4. Board-to-board connectors 5 Contact 6 Housing 6A Housing bottom 6B Housing top 7 Cavity 10 Fixed part 10A bottom end 10B top end 11 Implementation Section 12 spring pieces 13 Contact point 15. First spring section 16. Second spring section 16A Upper slope 16B Downward slope 16C Bend part 16D curved section 16E Bend part θ angle Z Height position A (Solid line) B Thick line Z0 initial position Z1 connection location ZA restoration location ZB Restored Position

Claims

1. A board-to-board connector mounted on a first board and sandwiched between the first board and a second board, thereby electrically connecting a plurality of first electrode pads on the first board and a plurality of second electrode pads on the second board, Multiple contacts, A housing that holds the plurality of contacts, Includes, The housing has a lower housing surface that can face the first substrate and an upper housing surface that can face the second substrate. Each contact, A fixing part that is fixed to the housing, A mounting portion that protrudes from the aforementioned fixing portion and can be soldered to the corresponding first electrode pad, A spring piece extending from the fixed portion and having a contact portion that can contact the corresponding second electrode pad, Includes, The spring piece of each contact is A first spring portion extending between the contact portion and the fixed portion, A second spring portion extending from the contact portion in the direction viewed from the upper surface of the housing to the lower surface of the housing, Includes, In the aforementioned multiple contacts, When the board-to-board connector is mounted on the first board, the second spring portion is separated from the first board. When the spring piece receives a load from the second substrate, causing the contact portion to be displaced in the direction from the upper surface of the housing to the lower surface of the housing, the first spring portion deforms and the second spring portion deforms in contact with the first substrate. In at least one of the aforementioned multiple contacts, After the load is removed, the contact portion is displaced in the direction from the lower surface of the housing to the upper surface of the housing, and the second spring portion continues to contact the first substrate. Board-to-board connector.

2. A substrate-to-substrate connector according to claim 1, The second spring portion has at least one bent portion, Board-to-board connector.

3. A substrate-to-substrate connector according to claim 1 or 2, The second spring portion has a curved portion that is capable of contacting the first substrate and is convex in the direction viewed from the upper surface of the housing to the lower surface of the housing. Board-to-board connector.

4. A substrate-to-substrate connector according to claim 1 or 2, The aforementioned fixing portion is fixed to the housing by press-fitting. Board-to-board connector.

5. A substrate-to-substrate connector according to claim 1 or 2, The aforementioned fixing portion is fixed to the housing by insert molding. Board-to-board connector.

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